Transcript Document

‘How I do’ CMR in DCM
Dr Sanjay Prasad, Royal Brompton Hospital
London, UK. For SCMR August 2006
This presentation is posted for members of scmr as an educational
guide – it represents the views and practices of the author, and not
necessarily those of SCMR.
[email protected]
Cine
Dilated Cardiomyopathy

Unexplained dilatation and impaired contractile
performance of the left ventricle in the absence of
significant coronary artery disease

Prevalence – 38/ 100 000

Variable onset

A familial basis is seen in around 15% of patients
Dilated Cardiomyopathy: Causes

Idiopathic — 50 %

Myocarditis — 9 %

Infiltrative disease — 5 %

Peripartum cardiomyopathy — 4 %

Hypertension — 4 %

HIV infection — 4 %

Connective tissue disease — 3 %
Other — 10 percent

Felker et al, NEJM 2000
DCM: Diagnosis

Often late presentation

Annual mortality ~4% (>SCD)

Opportunity for detection at an early/preclinical
stage
CMR Evaluation of DCM

The first important aspect is determining LV and RV volumes,
ejection fractions and mass

We recommend the modified Simpson’s method rather than
biplanar assessment since it makes no assumptions on cardiac
morphology and is both more accurate and reproducible.

After piloting the 4ch and VLA views, retrospectively gated
gradient echo cine slices are taken from the base to apex

Typically 7mm slices with a 3mm gap.

Usually myocardial coverage is achieved in 9-10 slices
CMR Quantification
See the presentation ‘how I do’ LV volumes
Downloadable from www.scmr.org
T2 Imaging

In patients with an acute presentation of DCM,
T2-weighted imaging is recommended to look
for evidence of active inflammation/oedema.

The most likely cause for increased signal in the
absence of infarction will be due to myocarditis
Occasionally other conditions such as
sarcoidosis may also manifest in this way.

T2 Imaging
Patient with a dilated LV and evidence of increased mid-wall/subepicardial signal
on T2-weighted images in the anterolateral wall. The underlying diagnosis was
DCM post-myocarditis.
T2 Imaging

If the T2-weighted triple-inversion recovery sequence is
used, typical sequence parameters are :-

Slice thickness of 8mm
Surface and body coils
TR – 2x RR
TE- 65ms
TI – 170ms
Images are taken in the VLA, 4ch view, plus a full SA
stack
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Assessment of Fibrosis

The presence of replacement fibrosis can be detected using the
inversion recovery late enhancement technique following
gadolinium-DTPA administration.

In several recent studies, about 60% of patients with DCM
showed no detectable fibrosis.
30% showed mid-wall enhancement that correlates with fibrosis
on histology.
10% showed a typical pattern of infarction with subendocardial
rather than mid-wall enhancement. In the presence of normal
coronaries, this is likely to represent recannalisation, an embolic
episode or coronary spasm.


McCrohon J et al, Circulation 2003
Detection of Fibrosis: Inversion Recovery Sequence



Dosage of Gd-DTPA: 0.1-0.2mmol/kg
At 0.1mmol/kg, images are usually acquired
after about 5 minutes with a TI starting at
~340ms (every other heart beat).
At 0.2 mmol/kg, scans are acquired after about
15 minutes with a TI starting at ~250ms.
Detection of Fibrosis: Inversion Recovery Sequence

Tips to confirm mid-wall fibrosis and ensure that artefact is not being
detected are:-
1.
Phase swap each slice
2.
If mid-wall enhancement is seen, ensure that the TI is optimal and if need
be, repeat the slice with a different TI
3.
Cross-cut through any areas of suspected mid-wall enhancement
4.
If subendocardial enhancement is seen, reconsider the diagnosis or assess if
this reflects ‘bystander’ coronary disease
5.
It is normal to see some fibrosis around the LVOT and at the RV/LV septal
insertion points
Assessment of Fibrosis
In this example, no late enhancement is seen reflecting the absence
of detectable fibrosis
Assessment of Fibrosis
In this patient, there is evidence of mid-wall fibrosis (arrows)
Why assess fibrosis
-It may be prognostically significant
-It may indicate aetiology of LVF
-It may indicate response to treatment
-(beta-blockers/device therapy)
Assomull et al, JACC 2006 (In
press)
Assessment of Fibrosis

Although the prescan diagnosis was of DCM (normal
coronary angiogram), the CMR study shows extensive
subendocardial enhancement reflecting an ischaemic
aetiology
Follow-Up

This will be clinically determined

In a stable patient where the question is of
determining reverse remodelling, a reasonable
interscan interval would be about 12 months